U.S. patent number 4,978,490 [Application Number 07/243,418] was granted by the patent office on 1990-12-18 for full overlaying injection molding.
This patent grant is currently assigned to The Standard Products Company. Invention is credited to Norman C. Jackson.
United States Patent |
4,978,490 |
Jackson |
December 18, 1990 |
Full overlaying injection molding
Abstract
A trim molding for attachment to a vehicle includes a core
member having an outer periphery less than a predetermined
thickness. An end is formed at each end of the core member. An
outer layer is molded about one side of the core member and ends to
form a smooth continuous surface to the predetermined thickness and
to prevent a joint line from visually appearing between the ends
and the core member in the outer layer.
Inventors: |
Jackson; Norman C. (Livonia,
MI) |
Assignee: |
The Standard Products Company
(Cleveland, OH)
|
Family
ID: |
22918711 |
Appl.
No.: |
07/243,418 |
Filed: |
September 12, 1988 |
Current U.S.
Class: |
264/148; 264/263;
264/275; 264/294; 428/31 |
Current CPC
Class: |
B60R
13/04 (20130101); B29C 70/78 (20130101); B29L
2031/302 (20130101) |
Current International
Class: |
B29C
70/00 (20060101); B29C 70/78 (20060101); B60R
13/04 (20060101); B29C 045/14 (); B29C
047/04 () |
Field of
Search: |
;264/246,247,250,254,255,275,278,DIG.57,263,148,294 ;428/31 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lowe; James
Attorney, Agent or Firm: Harness, Dickey & Pierce
Claims
What is claimed is:
1. A method of making a trim molding for attachment to a vehicle,
said method comprising the steps of:
forming an elongated core member by extruding and cutting a
polymeric material to an outer periphery and length less than a
predetermined thickness and length;
forming an end at each end of the core member;
molding an outer layer of a polymeric material about at least a
portion of one side only of the core member and over said ends to
form an outer elongated layer over the core member to the
predetermined thickness and to provide a smooth continuous surface
from one of said ends to the other of said ends to thereby prevent
a transverse joint line from visually appearing in the outer
elongated layer between the ends and the core member.
2. A method as set forth in claim 1 including the step of securing
an elongated bright strip with lateral edge portions onto said core
member and molding said outer elongated layer over only said
lateral edge portions of said bright strip thereby leaving a
central portion of said bright strip exposed to view.
3. A method as set forth in claim 2 wherein said step of molding
the outer elongated layer is carried to by injection molding.
4. A method of making a trim molding for attachment to a vehicle,
said method comprising the steps of:
extruding a core member to an outer periphery less than a
predetermined thickness said core member having a bright area;
forming an end at each end of the core member;
injection molding an outer layer about one side only of the core
member to fill the space between the bright area and outer
periphery of the core member to form a smooth continuous surface
and to prevent a transverse joint line from appearing between the
ends and the core member.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a molding for attachment to a
vehicle, and particularly, to a trim molding having an outer layer
injection molded about a core member.
One conventional type of trim molding for attachment to automotive
vehicles, e.g. as body side molding, has included a solid metal
core. This type of molding was made by roll forming a flat strip of
metal into a predetermined shape and then extruding a polymeric
material about the core to form an outer skin thereon.
One disadvantage encountered during fabrication of such trim
moldings related to imperfections in the outer skin due to
vibrations set up in the metal during the extrusion step. The metal
core would transmit vibrations which would result in imperfections
in the outer skin. Ridges, or "chatter lines" would appear in the
outer skin due to the vibrations.
Another disadvantage of such trim moldings having metal cores
involves their end caps. End caps were generally attached or molded
to the end of the metal core and outer skin extrusion. This
arrangement, however, provided an unsightly joint line between the
end cap and the molding.
Another conventional method of making trim moldings involves
extruding a thermoplastic material (typically PVC) to the desired
shape and then injection molding ends on the cut ends of the
extrusion to give a finished appearance. However, this method also
suffers the disadvantage of providing a joint line between the end
of the extrusion and the molded end cap. It will be appreciated by
those skilled in the art that this method of manufacture requires
fine tolerances in order to obtain a satisfactory appearance of the
joint. If the extrusion is larger or smaller than the end cap, the
end of the extrusion and end cap will not mate precisely. This
leaves an unsightly condition requiring costly hand trimming and
the resulting appearance is undesirable.
It is an object of the present invention to provide an improved
trim molding overcoming the aforementioned disadvantages. Further
understanding of the present invention will be had from the
following description taken in conjunction with the drawings and
accompanying claims.
SUMMARY OF THE INVENTION
A trim molding for attachment to a vehicle includes a core member
having an undersized outer periphery. A length of core member is
selected and an outer layer is molded about the length of core
member and the ends thereof to form a smooth outer layer having a
predetermined desired outer periphery without any undesirable joint
lines. Accordingly, the present invention eliminates chatter lines
in the outer skin as occur when extruding over a metal core member.
Also, the present invention avoids any visible joint line between
end caps and core member.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of a prior art trim molding.
FIG. 2 is an elevational view of a preferred embodiment of the
present invention.
FIG. 3 is a sectional view taken along line 3--3 of FIG. 2.
FIG. 4 is a sectional view, broken away, taken along line 4--4 in
FIG. 2.
FIG. 5 is a sectional view, broken away, taken along line 5--5 in
FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A conventional prior art trim molding for attachment to a vehicle
(not shown) is generally shown at 10 in FIG. 1. Trim molding 10
includes a metallic core member (not shown) which is a cut length
of extrusion having thermoplastic layer 12 extruded thereon and
presenting a bright area or strip 13 extending along the length
thereof. The trim molding 10 has end caps 14 and 16 molded at
opposite ends. Joint lines 18 appear where end caps 14 and 16 are
molded to trim molding 10.
Now referring to FIGS. 2-5, a trim molding of the present invention
for attachment to a vehicle (not shown) is generally indicated by
the numeral 20. Trim molding 20 is suitable, for example, as body
side molding to prevent damage by door strikes and the like. Trim
molding 20 includes a thermoplastic core member 22. Core member 22
can comprise an inexpensive, even unsightly scrap material and can
be foam or solid. Solid, non-weatherable polyvinylchloride is
suitable material for core member 22. A bright strip 25 is secured
to surface portion 24 of core member 22 which has a dimensional
configuration or predetermined periphery somewhat less than that
desired in the final product. It will be appreciated by those
skilled in the art that bright strip 25 can be a conventional
metallized film such as aluminum metallized polyester film and
that, although not shown in the drawing, it is contemplated that a
protective transparent layer can cover bright strip 25.
Core member 22 has end portions 30, 32 at each end thereof. In
accordance with the present invention core member 22 is placed in a
suitable mold and an outer skin or layer 36 of thermoplastic
material is injection molded in a conventional manner over core
member 22 to provide a desirable outer surface and to
simultaneously provide end caps over ends 34. Outer layer 36 must
be of suitable high quality material such as uv protected polyvinyl
chloride, as it is exposed to sight and weather. The final outer
periphery of molding has a predetermined thickness determined by
the mold. The outer skin or layer 36 forms a smooth outer surface
on the core member and portions 30 and a continuous surface
therebetween and avoids ridges and joint lines between end caps and
the core member. Undersurface 28 of outer layer 36 overlaps the
lateral edges of bright strip 25 to protect bright strip 25 against
deterioration due to the weather elements.
Molding 20 can be attached to a vehicle in any conventional manner
as by use of 2-side adhesive tape applied to surface 26. Preferably
2-side adhesive tape is applied to surface 26 during extrusion of
core member 22 and before molding outer layer 36 thereon.
The present invention also provides a method of making a trim
molding. The method includes the steps of providing a core member
22 as by extruding and cutting a polymeric material to less than a
predetermined thickness and length; then injection molding a
thermoplastic material about one side of the core member 22 and the
ends thereof to form a smooth continuous surface on the end
portions thereof having a predetermined thickness and length
without a joint line appearing between end caps and the core
member.
The present invention having been described in an illustrative
manner, it is to be understood that modifications and variations of
the present invention are possible in light of the above
disclosure. It is, therefore, to be understood that the invention
is to be limited only by the scope of the appended claims.
* * * * *